Known firearms such as, for example, the M16 rifle or the M4 carbine, are provided with an incrementally adjustable shoulder stock, which may be completely removed from the firearm. A known adjustable shoulder stock is described in DE-OS 1553 885, which is depicted in FIGS. 1 and 2.
The shoulder stock 1 of FIGS. 1 and 2 includes a base plate 3 having a connecting piece (not shown) that is inserted into a portion (not shown) along an axis 102 of the shoulder stock 1 from the rear. The connecting piece defines a plurality of boreholes (not shown) that are opened toward the bottom of the shoulder stock 1. Additionally, the shoulder stock 1 includes a bolt 7 that is positioned substantially perpendicular relative to the axis 102. A spring (not shown) urges the bolt 7 upward and toward one of the plurality of boreholes. In operation, to secure the shoulder stock 1 relative to a firearm (not shown), the bolt 7 is urged upward by the spring and guided by a bore 104 of the shoulder stock 1 toward one of the plurality of boreholes into which the bolt 7 is received.
To couple the bolt 7 to a lever 9, a portion of the bolt 7 is positioned in a through hole 106 defined by the lever 9 and a cross pin 13 is inserted into an aperture 108 defined by the bolt 7. The cross pin 13 extends out of the aperture 108 through a first opening 110 and a second opening (not shown), which is opposite the first opening 110. The cross pin 13 may be pounded into the aperture 108, bent on either side, or may be a spring bolt. The lever 9 may be formed from a sheet metal material or a plastic material. In operation, the interaction between the spring, the bolt 7 and the lever 9, applies a force to the lever 9 that urges the lever 9 toward the shoulder stock 1.
A lower portion 15 (e.g., a cross bar) is positioned below an upper portion 112 of the shoulder stock 1 and extends longitudinally from the rear toward the front of the shoulder stock 1. Additionally, the lower portion 15 is partially positioned in a channel (not shown) defined by the lever 9. The interaction between the lower portion 15 and the lever 9 axially positions the lever 9 relative to the trigger (not shown) of the firearm and substantially prevents the lever 9 from twisting relative to the shoulder stock 1. Additionally, a gap 114 may be provided between the lower portion 15 and the lever 9.
The lever 9 is rotatable about an edge (not shown) adjacent the bolt 7 defined by the shoulder stock 1. In operation, to adjust the shoulder stock 1 relative to the firearm, the lever 9 is rotated relative to the shoulder stock 1 by applying a force to the lever 9 in a direction generally represented by arrow 116. As an end 17 (e.g., a rear end) of the lever 9 rotates toward a surface 118 of the shoulder stock 1, the lever 9 engages the cross pin 13, which moves the bolt 7 away from the borehole in which it is positioned. Specifically, the force applied to the bolt 7 via the lever 9 overcomes the force applied to the bolt 7 via the spring. Once the bolt 7 is disengaged from the borehole, the shoulder stock 1 may be adjusted (e.g., horizontally adjusted) relative to the firearm to a desired position.
In some instances, the lever 9 may be moved to adjust the shoulder stock 1 relative to the firearm without significant interruption during operations. Additionally, the connecting piece includes a downward protruding stop (not shown) that may be engaged by the bolt 7 when the shoulder stock 1 is fully extended (e.g., pulled toward the rear of the firearm) to prevent the shoulder stock 1 from being accidently removed from the firearm. However, when a significant force is applied to the end of the lever 9, the bolt 7 may be moved to a distance from the connecting piece such that there is a clearance (e.g., a gap) between an end (not shown) of the bolt 7 and the downward protruding stop and, thus, the shoulder stock 1 may be completely removed from the firearm.
As a result, during operation, the lever 9 may be accidently released if the end 17 of the lever 9 becomes entangled in a marksman's clothing and inadvertently moves the lever 9 downward such that a distance of the gap 114 decreases. Similarly, during operation, the lever 9 may be accidently released by rapid hand movements by the marksman in which a force is applied to the lever 9. In both instances, the marksman may inadvertently adjust or completely remove the shoulder stock 1 from the firearm.
Additionally, because the end 17 of the lever 9 protrudes relative to the shoulder stock 1, during training or combat missions, tree branches or other objects are susceptible to becoming entrapped between the end 17 and the shoulder stock 1. Additionally, the marksman may reach behind the end 17 and be injured by the lever 9 when the firearm recoils.
In an attempt to avoid some of the above described problems, the end 17 of the lever 9 may be rounded or beveled. However, to achieve the necessary leverage to rotate the lever 9 somewhat effortlessly, the lever 9 must thereafter be extended toward the rear of the shoulder stock 1 the length which was removed during rounding or beveling. As a result, the number of the plurality of bores defined by the connecting piece that enables adjustability is decreased, because the length of the shoulder stock 1 is increased.